… Benjamin Bloom’s research in the teaching of math found that teachers get better results when they begin the course with a brief pre-assessment of the skills students must have in order to be successful in the unit they are about to teach. They discover areas where students are lacking those skills, and then instead of beginning new content, the begin with several days of instruction aimed at the prerequisite skills. They repeat this process for every unit, asking “which skills must students have in order to be successful in this unit and how do I know if they have them.” The process works best when it is done by a collaborative team of teachers and the schedule is designed to have some of them teaching in the same period. They give the pre-assessment, look at the results, and then divide the students between them. One might take the group that needs support in learning the new skills, another works some students to practice those skills, and another presents practical problems to students who are called upon to apply the skills. After several days of this, the students return to their homeroom teacher and the new unit begins.

One might think that this process would have an adverse impact on student achievement because teachers couldn’t cover as much content. In fact, Bloom found just that opposite. The fact that students had acquired the necessary skills enabled teachers to move through the content more quickly and the results were dramatically higher. You can read about this in an article Bloom wrote years ago for Phi Delta Kappan magazine called, “The two-sigma effect.”